The transition zone is an ecotone between rivers and lakes. The ecosystem of this region is affected by the interaction between hydrodynamic conditions of rivers and hydrological conditions of lakes, and it has great productivity and intense community competition. Macrophyte community is an important part of wetland ecosystem, and its structure is also an important ecological index of transition zone. In order to clarify the response mechanism of large aquatic plant communities in the transitional zone to changing hydrodynamic and water quality conditions, experiments and model were conducted to research the biomass and community competition of Phragmites australis and Ceratophyllum demersum L., the dominant species of emergent and submerged plants in Baiyangdian Lake.
Results/Conclusions
The results showed that in Baiyangdian transition zone, the biomass of Phragmites australis and Ceratophyllum demersum L. tended to decrease with the increase of water inflow from the upper boundary. In the community competition, the dominance of Phragmites australis increased with the increase of water inflow from the upper boundary. Water depth and nutrient concentration were both the limiting factors of macrophyte community competition. To maintain the suitable macrophyte community structure and productivity in the transition zone, the suitable incoming water volume is between 150,000 and 550,000 cubic meters. It can guide the environmental flow control measures of Baiyangdian Lake to maintain the macrophyte community homeostasis in the transition zone.